This invention relates to the field of medical devices, and more particularly to those devices used to transfer a piercing pin from the port of one tube set to the port of another tube set.
One particularly important application for the present invention is in the field of peritoneal dialysis, where it is used for the treatment of chronic renal failure. In peritoneal dialysis, body waste is removed from the blood by placing a dialysis solution within the peritoneal cavity of the abdomen (through a permanent catheter in the patient) and allowing the solution to remain for a period of time. During this dwell period, waste material from the blood diffuses across the peritoneal membrane (a smooth transparent serous membrane lining the cavity of the abdomen), and into the dialysis solution placed within the peritoneal cavity. The fluid is then drained from the peritoneal cavity, through the permanent catheter and into a bag. A tubular piercing pin, which is attached to the permanent catheter, via a tube set is then transferred from the bag of spent dialysis solution to a bag of new dialysis solution. The new dialysis solution is then drained into the peritoneal cavity to begin the dialysis process again. The empty bag is rolled up during the dwell time, thus providing a high degree of mobility to the patient.
Chronic peritoneal dialysis, however, is not without its limitations. Because the permanent catheter is an open conduit into the patient's peritoneal cavity, there is a potential for introduction of bacteria and development of peritonitis. Patients utilizing this technique must therefore exchange the bag of spent dialysis solution for the bag of new dialysis solution under highly sterile conditions. Traditionally, this has required that the connections between the catheter and the dialysis solution bags be treated with antibacterial agents. The difficulty of maintaining adequately sterile conditions using such methods is compounded by the fact that many patients suffering from renal failure (and thus requiring some form of dialysis) are visually and/or strength impaired, or lack sufficient manual coordination to carry out the procedures necessary to maintain sterile conditions. Such patients also have difficulty transferring the piercing pin from an old to a new bag of dialysis solution.
A number of devices have been developed to assist patients in exchanging dialysis solution bags while maintaining sterile conditions. For example, U.S. Pat. No. 4,655,753 discloses a device having a lever for manually exchanging a piercing pin from a first container to a second container without touch contamination by the user. U.S. Pat. No. 4,541,82 discloses a similar device having a track that guides a piercing pin from a first container to a second container. U.S. Pat. No. 4,500,788 discloses a device for removing a piercing pin from a container by moving a lever upward, and inserting a piercing pin into a new container by moving the lever downward. The piercing pin and connecting portion of the container are subjected to ultraviolet radiation. U.S. Pat. Nos. 4,557,727 and 4,405,315 disclose a device having a manually operated lever whose motion is limited by a track for guiding the piercing pin from one container to another container.
Although such devices exchange the piercing pin without the user having to touch the connections, the exchange still requires manual operation. Patients with extreme strength impairment can have difficulty even with these devices. Since these devices are operated manually, there is also a possibility that the patients using devices equipped with UV sterilizing bulbs may not allow the connections sufficient time to become completely sterile under ultraviolet radiation. Thus, most devices still rely on the physical ability and judgment of the patient to assure sterile conditions.